[cc] Pass on BeginFrameAcks from CompositorEBFS through RWHVAura, DFH.

cc/ipc/compositor_frame_metadata_struct_traits.cc

Index: cc/ipc/compositor_frame_metadata_struct_traits.cc
diff --git a/cc/ipc/compositor_frame_metadata_struct_traits.cc b/cc/ipc/compositor_frame_metadata_struct_traits.cc
index cdef417d159f6ca7216509f9124cb88c9e041b48..4ef76c23c637f993a7e8cfcc0fe4f16fc03ce5bd 100644
--- a/cc/ipc/compositor_frame_metadata_struct_traits.cc
+++ b/cc/ipc/compositor_frame_metadata_struct_traits.cc
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "cc/ipc/compositor_frame_metadata_struct_traits.h"
+#include "cc/ipc/begin_frame_args_struct_traits.h"
 #include "cc/ipc/selection_struct_traits.h"
 #include "cc/ipc/surface_id_struct_traits.h"
 #include "ui/events/mojo/latency_info_struct_traits.h"
@@ -43,7 +44,8 @@ bool StructTraits<cc::mojom::CompositorFrameMetadataDataView,
       data.can_activate_before_dependencies();
   return data.ReadSelection(&out->selection) &&
          data.ReadLatencyInfo(&out->latency_info) &&
-         data.ReadReferencedSurfaces(&out->referenced_surfaces);
+         data.ReadReferencedSurfaces(&out->referenced_surfaces) &&
+         data.ReadBeginFrameAck(&out->begin_frame_ack);
 }
 
 }  // namespace mojo